1. Technical Field
The present disclosure relates to a sensor control method executed by an air-conditioning apparatus. More specifically, the present disclosure relates to, for air conditioning and other applications, an infrared-sensor control scheme and image processing that enhance the recognition performance of an infrared sensor and that enhance the image resolution of a thermal image acquired by the infrared sensor.
2. Description of the Related Art
For air-conditioning apparatuses, infrared sensors have been utilized to obtain the temperature environment and the presence of people in an air-conditioned space. The air-conditioning apparatuses utilize data of the temperature environment and the presence of people to control an air temperature, the direction of an air flow, the strength of the air flow, and so on to thereby realize comfortable air conditions for the people in the air-conditioned space. The air-conditioning apparatuses may also utilize the data for other applications, such as detecting a fire in the air-conditioned space and issuing a fire alarm.
Infrared sensors are classified into two types according to their structures. One of the types is a line infrared sensor in which infrared light-receiving elements are arranged in one line. A line infrared sensor described below in the present disclosure also encompasses an infrared sensor in which infrared light-receiving elements are arranged in a plurality of lines. The other type is a matrix infrared sensor in which infrared light-receiving elements are arranged in a flat plane. Although the present disclosure will be described using mainly a line infrared sensor, a matrix infrared sensor may also be used.
In order to obtain a thermal image of an air-conditioned space, the line infrared sensor scans an entire area of interest. Line image data acquired at different scan angles are used to construct a planar image for subsequent image processing for recognizing a target object or a thermal event in the air-conditioned space. However, since the number of infrared light-receiving elements in the line infrared sensor is small, the resolution of the acquired planar image is low. Consequently, details of a target object or a thermal event in the air-conditioned space can hardly be recognized.
In order to overcome the problem of the low resolution, super-resolution reconstruction, which is one type of image processing method, is utilized. The super-resolution reconstruction is performed as countermeasures against image deterioration due to image digitization involving a motion effect, a bokeh effect, and a downsampling effect. Obtaining different views of an image by utilizing optical characteristics of the infrared sensor in conjunction with the image processing makes it possible to enhance the resolution of the image. Accordingly, it is possible to better recognize details of a target object or a thermal event in the air-conditioned space without involving an increase in the number of infrared light-receiving elements in the infrared sensor, the increase causing an increase in the cost of the infrared sensor.